Disposable anesthesia-breathing circuit unit

ABSTRACT

This application discloses an anesthesia gas delivery system to be coupled between an anesthesia machine and a patient so as to form part of a complete breathing circuit. This system includes conduits coupled to an intermediate connector which, in turn, is applied to the patient using a face mask forming a part of the system or an endotracheal tube. It further includes a breathing bag to be connected at the appropriate place in an anesthesia machine. In order that the system may be disposable after single patient use and to provide for patient safety, there is included a filter for removing harmful particles from gas circulating in the system. In addition, all elements in the system are arranged to be electrically conductive or antistatic to avoid the danger of explosion.

United States Patent Dean R. Wallace [72] lm'entor Madison, Wis. {21]Appl, No. 860.869

[22] Filed [45] Patented [73] Assignec [54] DISPOSABLEANESTHESIA-BREATl-IING CIRCUIT UNIT 19 Claims, 15 Drawing Figs.

[52] U.S.Cl 128/188 [51 1m.c1 As n 1o [50] Field of Search 128/188,

141, 142, 187- 191, i iiii ieizi i i ii ri4&5, 146.6, 146.7, 202, 145.8,203

[56] References Cited UNlTED STATES PATENTS 2,381 ,568 8/1945 Booharin128/141 2,875,759 3/1959 Ga1leher..... 128/146 Primary Examiner-Adele M.Eager Assistant Examiner-J. B. Mitchell Attorneys-Edmund W. Bopp, H.Hume Mathews and Larry R. Cassett ABSTRACT: This application disclosesan anesthesia gas delivery system to be coupled between an anesthesiamachine and a patient so as to form part of a complete breathingcircuit. This system includes conduits coupled to an intermediateconnector which, in turn, is applied to the patient using a face maskforming a part of the system or an endotracheal tube. It furtherincludes a breathing bag to be connected at the appropriate place in ananesthesia machine. In order that the system may be disposable aftersingle patient use and to provide for patient safety, there is includeda filter for removing harmful particles from gas circulating in thesystem. 1n addi- 1 tion, all elements in the system are arranged to beelectrically conductive or antistatic to avoid the danger of explosion.

PATENTED JAN 1 9 I97! SIIZU 3 CF 5 v FIG. 6

lNVENTOR DEAN R. WALLACE fioRNEY -PATENTEUJAN1-9191}- 3556;097

FIG. 7

INVENTOR DEAN 'R. WALLACE ATTORNEY PATENTED JAN 1 s I97| SHEET 5 BF 5INVENTOR DEAN R. WALLACE QM PCWJ A TORNEY DISPOSABLEANESTHESlA-BREATHING CIRCUIT UNIT This application is acontinuation-in-part of application 748,524 filed July 29, i968, nowabandoned. BACKGROUND OF THE lNVENTlON This invention relates generallyto systems for'supplying gases for respiration by living things. Morespecifically, it relates to apparatus for supplying anesthetics to humanbeings.

As used in this application, the breathing circuit includes all theelements of a gas delivery system (defined below) and certain elementsof the anesthesia machine such as relief valves. gas inlet; vaporizer(if needed), soda-lime absorbers and the conduitsinterconnectingthem.The term gas delivery system includes the face mask (or endotrachealtube) and the flexible tubing and connectors coupling these elements toan anesthesiamachine. lt also includes a breathing bag and in theparticular context of this application a filter as willbe developedsubsequently.

It is important to keep in mind as one attempts to appreciate thisinvention and its background that a surgical procedure on a human beingis always a critical matter and as it proceeds in an operating room, itis vital that many things seemingly small and isolated perform withoutcreating "mechanical problems. Therefore, reliability of apparatus andthe avoidance of new-problems while seeking to solve old ones areabsolute essentials. in the context of this invention, this means thatany attempt to change a long standing surgical practice by introducing anew approach in operating room procedures and apparatus will and shouldbe evaluated in very large part on. its ability to perform as welli asor better than what is presently available So where there isexistingapparatus for which standards of performance and desired objectives haveevolved over the years any degradation in these is not only undesirablebut perhaps noteven permissible. it is not overstating the,matter to saythat this is particularly true of systems supplying anesthetics.

ln contemporary medical practice a number of clearly delineatedstandards or objectives have developed with respect to the natureandcapabilities of apparatus for supplying anesthetics to patientsundergoing surgical or other therapeutic procedures. These standards, inlarge part, are concerned with the effectiveness and safety of theapparatus.

Such standards include, among others, the need to supply the anestheticto the patient in quantities which can be controlled and in such amanner that its effect can be assessed by the anesthesiologist. Thus, inan anesthesia-breathing circuit there is usually included a breathingbag which serves as a means by which the anesthesiologist senses thepressure exerted by the patient as he exhales. The bag also functions asa gas reservoir which may be squeezed by the anesthesiologist to providepressure for manual ventilation of gas being inhaled by the patient, ifnecessary. A breathing bag, in order to serve these purposes well, musthave certain qualities. Firstly, the bag should not be noticeablydistensible. Were it to do so the anesthesiologistwould have a difficulttime controlling the gas pressure and volume. Secondly, it should havewhat might be termed as good feel characteristics, it should be thinenough or feel thin enough for the anesthetist to sense the pressurebeingexerted on the patients respiratory system when he is ventilatingthe patient. Another quality which should be present relates to thesurface of the bag which should exhibit a slight tackiness so that itmay be grabbed or squeezed without having ones hands slip off.

Anpther element in anesthesia circuit which is expected to have certaincapabilities is the face mask held on the face of the patient andthrough which the gas is delivered. It is important that the mask have aminimum of dead air space. By this is meant that the space between theportions of the face encompassed by the mask and the interior masksurface be at a minimum. The reason for this is that it is desired tominimize the amount of the patients exhaled breath which he rebreatheson the next inhalation. Minimum dead air space also allows theanesthesiologist to have the best possible control of gas mixturesavailable to the patient. In addition, it is important that a good sealbe maintained between the surface of the patients face and the mask inorder to minimize gas leakage and again to insure that the'patientreceive the desired quantity of gas. Another desired quality is the evendistribution of pressure about the patients face in order to avoidpressure points. The objective inthis instance is the desire to avoidtraumatic situations such as skin irritation or other injury caused byexcessive pressure at any point on the face. To the extent consistentwith these objectives, the weight of the mask should be kept as low aspossible to obtain greater patient comfort.

ln addition to the elements that have been discussed. the anesthetic gasdelivery system includes the tubes and connectors for supplying the gasto the patient and returning the patients exhaled breath to the machine.The breathing bag discussed above is connected to that portion of thegas flow circuit included as a part of the machine but is consideredherein as a part of the anesthesia gas delivery system.

Such a system, in addition to having the qualities discussed above,should be electrically conductive, to avoid sparking which could resultfrom the buildup of electrical charges. Many anesthetic gases as well asother types of gases used in operating rooms are potentially explosiveand could be set off. by such sparking. The system shouldlalso preventthe transinission of particles such as bacteria from one patient toanother. Insofar as prior art systems are concerned, the objective ofremoving bacteria has been met by cleaning and sterilizing.

There are in existence a number of gas delivery systems which come nearmeeting or do meet all these features. However, they do this berequiring the 'use of expensive materials and relatively expensivemanufacturing procedures. Consequently, their cost is relatively high.As pointed out, in order to reuse them they must be cleaned andsterilized to minimize the possibility of cross infection from onepatient to another. Sterilization procedures take time and require theuse of personnel and equipment which adds to their overall cost. Theincreased safety which could be obtained with a single use unit makessuch a system highly desirable if one could be produced cheaply enoughto make its adoption economically feasible.

SUMMARY OF THE lNVENTlON Therefore, it is an object of this invention toprovide a single use anesthesia-breathing circuit which, while capableof meeting or exceeding the standard of performance expected in suchunits, will at the same time provide the capability of substantiallyreducing the possibility of cross contamination.

It is another object of the invention to provide an anesthesia-breathingcircuit which is capable of protecting the operation room environmentfrom infection caused by infectious particles which may be present in apatient s exhalation.

It is another object of this invention to provide ananesthesia-breathing circuit which is capable of protecting a patient onwhom it is being used from cross infection as the result of a prior useof the anesthesia circuit on another patient.

These and other objects are achieved by providing ananesthesia-breathing circuit system which is fabricated out of materialsand uses manufacturing techniques which tend to substantially reduce thecost of such units and render them disposable. The system is madeelectrically conductive to minimize the risk of 'lexplosion and includesmeans to remove harmful particles so as to substantially reduce the riskof cross infection from one patient to another or other harm to apatients respiratory system.

BRIEF DESCRIPTION OF THE DRAWINGS in the light of the drawings in which:

FIG. 1 is a schematic view of an anesthetic circuit constructed inaccordance with the invention;

FIG. 2 is a front view of a disposable face mask forming a part of theinvention;

FIG. 3 is a cross section view along the line 3-3 of FIG. 2',

FIG. 4 is a planar view of a preferred form of a connector for use inthe invention;

FIG. 5 is a front view of one element of the connector;

FIG. 6 is a cross-sectional view of another element of the connector;

FIG. 7 is a front view of a breathing bag forming a part of theinvention;

FIG. 8 is a top view taken along the line 8-8 of FIG. 7;

FIG. 9 is a side view of a connecting bushing for use with the breathingbag:

FIG. 10 is a planar view of a filter for use in the invention;

FIG. 11 is an exploded view of the filter of FIG. 10',

FIG. 12 is a cross-sectional view of the filter taken along itslongitudinal axis;

FIG. 13 is a cross-sectional view of the filter taken along itstransverse axis;

FIG. 14 is an illustration of an alternative location of a filter foruse in the invention; and

FIG. 15 is an illustration of still another alternative embodiment ofthe invention.

DETAILED DESCRIPTION FIG. 1 of the drawing illustrates generally ananesthesiabreathing circuit wherein the invention may be used andfurther illustrates the invention in use and forming a part of acomplete anesthetic delivery system. This figure schematicallyillustrates a face mask (or endotracheal tube) 2 to be attached to apatient. A coupling element as in this embodiment takes the form of aconnector 3 having a tee element 4 for attaching the connector to themask and including two tube elements 5 connecting to a pair ofcorrugated conduits 6 and 7. The conduit 6 connects with a breathing bag8 through a check valve assembly 10 while conduit 7 connects with afilter 9 for removing infectious media, such as bacteria, from thesystem.

As the gas exhaled by the patient flows through the conduit 6 (shown bythe arrows), it passes through the check valve assembly 10 which permitsunidirectional flow to the breathing bag 8 and prevents back flowthrough the conduit 6 if the bag is squeezed. An anesthesia machine towhich the disposable elements constituting the invention are to beconnected includes the check valve and the elements in the flow circuitextending from the bag to the filter 9. A pressure relief valve 13 isconstituted by a spring 14 which biases a valve head 15 onto seat 16 ina closed position. This valve permits pressure relief when the pressurein the conduit 11 exceeds the pressure on the head 15 exerted by thespring 14. Conduit 11 connects to an exhalation check valve assembly 17which maintains unidirectional flow and prevents exhalation flow throughthe inhalation side of the circuit. A pressure gauge 18 may beprovided'in order to read back pressure before the conduit connects withan absorber apparatus 12.

The absorber apparatus 12 includes a bypass valve 19 comprising arotatable element sealed against the walls of the canister of the valveand which permits flow through sodalime maintained in the canister forabsorption of the carbon dioxide in the exhalation. The soda-lime may bebypassed by rotating the closure element 90".

As the gas flow exits the absorber apparatus 12, fresh gas (oxygen,nitrous oxide, etc.) may be added through an inlet 20. The flowthereafter may move through a vaporizer 21 either by bubbling orotherwise and then pass through the filter 9. It should be appreciatedthat the elements 10 through 21 constitute parts of the anesthesiamachine and are shown in a schematic form for these are well-known inthe art and do not form a part of the invention. Therefore, in theembodiment of the invention illustrated in FIG. 1, it is constituted bythe face mask 2, the connector 3, the conduits 6 and 7, the breathingbag 8 and the filter 9.

A first element to be discussed is the face mask 2. This mask is shownin FIGS. 2 and 3 as having a cone or relatively thin face piece 22. Thecone is preferably made of a conductive vinyl plastic using injectionmolding or vacuum forming techniques. It includes an edge portion 23which has integrally formed therewith a first surface 24 which extendsslightly outwardly in a direction on one side which may be termed theforward direction. The first surface 24 blends into a second surface 25which is relatively flat. Extending outwardly in the forward directionof the face piece 22 is a nose accommodating portion 26. Formed in theface plate below the portion 26 is a gas supply tubing attachment 27encompassing an opening 28 in the face plate.

A cushion 29 is formed in place onto the other side 30 of the face plateto form with the face plate a face mask which resiliently conforms tothe wearers face. The cushion 29 has a relatively wide base or bottomportion 31 secured to the surface 30 and a relatively narrow top portion32 which provides a contoured surface to engage the surface of thepatients face.

By particular reference to FIG. 3 it may be seen that the face mask whenapplied to the face of a patient may be pressed gently against the faceso that the contoured surface conforms to the contour of the face. Inaddition the cushion 29 being formed of a foamed plastic materialcompresses, it being noted that the amount of compression may becontrolled by hand pressure or by a head strap (not shown) used tosecure the mask to the patient's face and held on the mask by the studs34. In addition, by providing a deformable wire 35 formed of anysuitable material on the underside of the surface 24 and retained inpart by the foamed cushion 29, the face plate may be bent to any desiredshape to better accommodate the facial contours of a particular patient.When applied and secured in the manner indicated, the patients nose andmouth will be positioned very close to the face plate 22. In thesecircumstances, some portion of the nose will be positioned within thenose-accommodating portion 26. Consequently, there will be a minimum ofspace between the inner surface of the mask and the patients face. Theminimizing of this space (dead air space) is a main consideration in theconstruction of a face mask in order to eliminate as much as possiblethe patients exhalation which is rebreathed on a subsequent inhalation.

In addition to the foregoing, the deformable cushion 29 will function tomaintain a good seal between the mask and the patients face. Also itwill act to evenly distribute the pressure of the mask over the surfaceof the face and thus minimize the possibility of skin trauma.

Cushion 29 may be made conductive by forming it ofa conductive materialor by coating it with a liquid containing carbon particles by a dip orspray process. Obviously, other conductive materials which may beapplied to the surface of the foamed cushion 29 are suitable and may beused.

In the embodiment of the invention illustrated, the means for connectingthe conduits 6 and 7 to the mask is shown in detail in FIGS. 4 through6. Connector 3 is comprised of a tee element 4 and two connectorelements 5. The connector elements 5 are mounted on the tee element 4 sothat they may swivel thereon.

As shown in FIG. 5, the tee element 4 is a hollow member which comprisesa tubular head portion 36 and a tubular leg portion 37. The leg portion37 has an outside diameter 38 for secure insertion in the tubularattachment 27 of the mask 2. Its inside diameter 39 is dimensioned to beof a size so as to securely receive a commonly used endotracheal tubeconnector if such is desired to be used. The head portion 36 is providedwith a pair of annular grooves 41 which are formed by tapered first andsecond ribs 41 and 42.

Each connector element 5. as shown in FIG. 6, comprises a tubular member43 having a circumferential abutment 44 and a tapered end 45facilitating the positioning of the corrugated conduits 6 and 7 on thetubular member 43. Each element 5 also includes an opening 46 at anangle to its longitudinal axis, the periphery of which is formed by anannular rounded projection 47. The diameter of the opening 46 isselected to be less than the diameter of the groove 40 in order that theelement 5 may be positioned on the tee element 4 using a relativelylight force and be maintained thereon when the surface 47 engages in thegroove 40.

Sincean interference fit is used to connect the elements 5 to element 4and these elements are made of a plastic material, it is desirableduring assembly process to soften the elements at the connecting points,preferably adjacent the surfaces 47. with heat in order to temporarilyincrease the elastic properties of the material. When heated withresulting increased elasticity, the surfaces 47 are forced over thetapered ribs 41 to be retained in the grooves 40. After cooling, theconnection of the elements 4'and 5 will provide a swivelingsubstantially gastight connector with the elements 5 rotatable withrespect to the element 4. Both .of these elements may be injectionmolded of conductive plastic material. However, they could be made froma nonconductive material with some other means used to provide thedesired electrical conductivity.

The disposable breathing bag 8 is shown in detail in 7 through 9 andcomprises four side panels 48-51, two of which, 49 and 51, are gusseted.The panels 49, 50, and 51 are preferably made of antistatic vinylplastic. These materials are selected so that the resultant dielectriccharacteristics of the bag may be used to heat seal the edges of thepanels to form the desired enclosure. Thus, after the panels have beencut to shape,l dielectric heating apparatus may be used to .seal theedges.

Breathing bags formed in accordance with this aspect of the inventionhave been fabricated out of 0.010 inch thick vinyl in a particularapparatus embodying the invention. When so fabricated. they have beenfound to be thin enough to permit the anesthesiologist to feel thepressure being exerted on the patient's respiratory system. ln addition,they have been found to have a good compliance characteristic. That is,they do not distend as gas is forced out of the bag when pressure isexerted on it. Also, the surface of the bag exhibits a degree oftackiness so that the possibility of hands slipping from the bag as itis gripped is considerablydiminished.

The bag is formed to have a neck 52 having an outwardly flaring rim 53to facilitate the reception of a bushing 54 therein. The neck 52 isformedof extensions of side panels 48 and 50. Bushing 54 is preferablymade of a conductive plastic having an extension 55 of lesser outerdiameter and provided with a tapered end 56. in order to assemble andsecure the bushing 54 in the bag 8, an adhesive is applied to theextension 55 up to a shoulder 57. The bushing is then inserted in theneck 52 up to a shoulder 57. The bushing is then inserted in the neck 52and the adhesive dried and/or cured so as to maintain the bushing inposition. If desired, the bushing may be further secured and sealed inthe bag by tape 58 wrapped tightly around the neck. Preferably, the tapemay be made of vinyl plastic. Alternatively, ultrasonic or dielectricwelding means may be used to further secure the bushing to the bag.

The conductive vinyl bushing makes intimate contact with the neckextension of the conductive panel 48 of the bag and thereby provides aconductive chain to the metal structure of the anesthesia machine. Thus,the bag by virtue of its structure and connection to the machine, aswith the other elements of a disposable breathing circuit in accordancewith the invention, substantially eliminates the buildup of electricalcharges.

As noted above. it is important that cross infection between patients beeliminated with apparatus of the type disclosed. in this embodiment ofthe invention, it is proposed to accomplish this by providing thebacteria filter 8. FIGS. through 13 illustrate a filter which may beused for this purpose. in FIG. 10, the construction of such a filter isgenerally shown. The filter comprises a housing formed of a conductiveplastic material having a body 58 and a cap 59. These are both hollowmembers and enclose the filter member 60 shown in FIGS. 11 and 12. Thebody 58 has an inlet 61 and the end cap 59 has an outlet 62.

The filter 9 may be formed of a cellulose and glass fibrous material 60bonded with epoxy resin. its physical structure isv constituted by anannulus of corrugated filter material secured to end plate 64. Thefilter is bonded by any suitable means such as by the use of an adhesiveto the interior surface of the end cap 59. its longitudinal extent issuch that when so bonded and when the end cap is fitted over the wideend of the housing 58, the end plate 64 will be spaced a distance fromthe opening of the inlet 61. Likewise. its diameter is selected to beone which will provide a space between the filter and the wall of thehousing 58. By virtue of this arrangement gas passing through the systempreferably enters through the inlet 61 and passes through the filtermaterial and out the outlet 62.

A filter of the type described has been found effective to achievesubstantially percent elimination of the bacteria which may be carriedby the gas as it passes therethrough. Ex-

amples of bacterial species whichhave a morphology of the coccus typeare staphylococus aureus and streptococcus. These bacteria have averagediameters of 0.8 and 0.5 to L0 microns, respectively. Bacterial specieshaving a morphology ofthe rod type which have been eliminated using afilter in ac cordance with the invention include escherichia colli,pseudomonos aeruginosa, salmonella and mycobacterium tuberculosis whichhave dimensions ranging from 0.2 to 0.8 by l to 4 microns.

While in FIG. 1 the filter 9 is shown as being provided between the endof the conduit 7 and the vaporizer 21, it need not be mounted solely inthat location. in that location it in effect serves to protect thepatient from bacteria which may have been transmitted into theanesthesia machine as the result of previous patient usage. On the otherhand, it may be desirable to protect the anesthesia machine and theentire operating room environment from a highly infectious patient. lfthis be so, the filter may be mounted between the connector 3 and theface mask 2. This embodiment is shown in FIG. 14. FIG. 15 illustratesanother embodiment of the invention where the filter 9 is connectedbetween the end of the conduit 6 and the anesthesia machine to protectit from contamination by a highly infectious patient.

The invention itself in its various aspects and embodiments has beendescribed and shown in the accompanying drawings, all of which areintended as illustrative, and the invention itself is limited only asset forth in the claims.

lclaim:

l. in an anesthesia gas delivery system for providing an anesthetic gasto a patient including a face mask, first and second conduit means,connector means to connect said first and second conduit means to saidface mask, said first conduit means receiving fluid exhaled from thepatient, first check valve means connected to said first conduit meansto prevent a reverse flow of the exhaled fluid in said first conduitmeans, a breathing bag associated with said first check valve mean,relief valve means in fluid communication with said first check valvemeans, exhalation check valve means in fluid communication with saidrelief valve means, absorber means receiving the exhaled fluid, fluidinlet means for adding fluid to the exhaled fluid, anesthetic vaporizermeans receiving the exhaled fluid and adapted to provide fluid forinhalation, said anesthetic vaporizer communicating with said secondconduit means, and a filter means removing extraneous particles fromfluid circulating in the system, the improvement wherein the face mask,connector means, first and second conduit means and the filter means aredisposable and readily detachable from said first check valve means andsaid vaporizer means after use.

2. An anesthesia gas delivery system as defined in claim 1 wherein saidface mask has a first element comprising a relatively thin moldedplastic face piece having: an edge surface; a first integral surfaceextending outwardly from said edge surface on one side of and toward thecenter of said face piece; a second integral surface extending from saidone side and toward the center of said face piece from said firstsurface; a nose-accommodating portion extending from said second surfaceon said one side and having an opening formed thereinbclow saidnose-accommodating portion; and a second element comprising a foamedplastic compressible cushion secured to and extending from the otherside of said face piece to engage the surface of the face surroundingthe nose and mouth.

3. An anesthesia gas delivery system as defined in claim 2 wherein saidcushion is coated with a conductive material.

4. An anesthesia gas delivery system as defined in claim 2 wherein saidcushion has a relatively thick bottom secured to said other side of saidface piece and tapers toward a thinner face-engaging surface.

5. An anesthesia gas delivery system as defined in claim 2 wherein saidface mask is provided with integrally formed projections extending fromsaid one side thereof to receive straps for holding said face mask tothe face.

6. An anesthesiagas delivery system as defined in claim I wherein saidfirst conduit means has one end connection for coupling to the firstcheck valve means and a flexible tube extending from said one endconnection; said second conduit means has one end connection forcoupling to the anesthetic vaporizer means and a flexible tube extendingfrom its said one end connection; and said connector means comprises acoupler having first and second openings connected to the free ends ofsaid flexible tubes of said first and second conduit means,respectively, and a third opening connected to said face mask.

7. An anesthesia gas delivery system as defined in claim 6 wherein saidcoupler comprises: a cross tube having end openings and an openingintermediate its ends; an integral tube extending from said tube havingaccess to said intermediate opening, said intermediate tube connected tosaid face mask; and a connector tube swiveled on each end of said crosstube around said end openings providing the connections to said freeends of said flexible tubes of said first and second conduit means.

8. An anesthesia gas delivery system as defined in claim 7 wherein saidfilter means is connected to said flexible tube of said first conduitmeans to constitute its said one end connection.

9. An anesthesia gas delivery system as defined in claim 7 wherein saidfilter means is provided on said coupler.

10. An anesthesia gas delivery system as defined in claim 7 wherein saidfilter means is connected to said flexible tube of said second conduitmeans.

11. An anesthesia gas delivery circuit as defined in claim 1 whereinsaid breathing bag is readily detachable from association with saidfirst check valve means and is disposable.

12. An anesthesia gas delivery circuit as defined in claim 11 whereinsaid breathing bag comprises a plurality of panels joined along theiredges and made of antistatic material and at least one panel including aconductive portion.

13. An anesthesia gas delivery circuit as defined in claim 11 whereinsaid breathing bag comprises a plurality of panels joined along theiredges made of an antistatic material.

14. An anesthesia gas delivery circuit as defined in claim 11 whereinsaid breathing bag comprising four panels joined along their edges.

15. An anesthesia gas delivery circuit as defined in claim 12 whereinsaid breathing bag includes a neck and a bushing joined to said neck.

16. In an anesthesia gas delivery system for providing an anesthetic gasto a patient including a gas communication means adapted to be placed incontact with a patient. connector means in gas flow relation to saidcommunication means and having a pair of connector elements, first andsecond conduits each having one end in gas flow relation to a respectiveone of said pair of connector elements. said first conduit receivingfluid exhaled from the patient. first check valve means connected tosaid first conduit to prevent a reverse flow of exhaled fluid in saidfirst conduit, a breathing bag associated with said first check valvemeans, relief valve means in gas flow relation to said first check valvemeans, exhalation check valve means in gas flow relation to said reliefvalve means, absorber means in gas flow relation to said relief valvemeans fluid inlet means for adding an additional fluid to the gas flow,anesthetic vaporizer means in gas flow relation to said absorber means,said anesthetic vaporizer being connected to said second conduit toprovide fluid for inhalation to the patient, and a filter means removingextraneous particles from the gas flow through the system, theimprovement wherein the gas communication means, connector means, firstand second conduits and the filter means are disposable and readilydetachable from said first check valve means and said anestheticvaporizer means.

17. The system set forth in claim 16 wherein said communication means isa face mask and said mask comprises a conductive plastic face piece anda foam plastic cushion adapted to resiliently conform to the facialcontour of the patient and having a gas supply tube attachment means andwherein the cushion has a conductive coating. I

18. The system set forth in claim 16 wherein said connector means has aY configuration and comprises a hollow tee element having a leg and ahead with the leg of said tee element connecting to said communicationmeans, and said connector elements are rotatably fitted on opposite endsof the head and wherein said connector means is made of electricallyconductive plastic material.

19. The system set forth in claim 16 wherein said first and secondconduits are corrugated tubes made of electrically conductive material.

1. In an anesthesia gas delivery system for providing an anesthetic gasto a patient including a face mask, first and second conduit means,connector means to connect said first and second conduit means to saidface mask, said first conduit means receiving fluid exhaled from thepatient, first check valve means connected to said first conduit meansto prevent a reverse flow of the exhaled fluid in said first conduitmeans, a breathing bag associated with said first check valve mean,relief valve means in fluid communication with said first check valvemeans, exhalation check valve means in fluid communication with saidrelief valve means, absorber means receiving the exhaled fluid, fluidinlet means for adding fluid to the exhaled fluid, anesthetic vaporizermeans receiving the exhaled fluid and adapted to provide fluid forinhalation, said anesthetic vaporizer communicating with said secondconduit means, and a filter means removing extraneous particles fromfluid circulating in the system, the improvement wherein the face mask,connector means, first and second conduit means and the filter means aredisposable and readily detachable from said first check valve means andsaid vaporizer means after use.
 2. An anesthesia gas delivery system asdefined in claim 1 wherein said face mask has a first element comprisinga relatively thin molded plastic face piece having: an edge surface; afirst integral surface extending outwardly from said edge surface on oneside of and toward the center of said face piece; a second integralsurface extending from said one side and toward the center of said facepiece from said first surface; a nose-accommodating portion extendingfrom said second surface on said one side and having an opening formedthereinbelow said nose-accommodating portion; and a second elementcomprising a foamed plastic compressible cushion secured to andextending from the other side of said face piece to engage the surfaceof the face surrounding the nose and mouth.
 3. An anesthesia gasdelivery system as defined in claim 2 wherein said cushion is coatedwith a conductive material.
 4. An anesthesia gas delivery system asdefined in claim 2 wherein said cushion has a relatively thick bottomsecured to said other side of said face piece and tapers toward athinner face-engaging surface.
 5. An anesthesia gas delivery system asdefined in claim 2 wherein said face mask is provided with integrallyformed projections extending from said one side thereof to receivestraps for holding said face mask to the face.
 6. An anesthesia gasdelivery system as defined in claim 1 wherein said first conduit meanshas one end connection for coupling to the first check valve means and aflexible tube extending from said one end connection; said secondconduit means has one end connection for coupling to the anestheticvaporizer means and a flexible tube extending from its said one endconnection; and said connector means comprises a coupler having firstand second opEnings connected to the free ends of said flexible tubes ofsaid first and second conduit means, respectively, and a third openingconnected to said face mask.
 7. An anesthesia gas delivery system asdefined in claim 6 wherein said coupler comprises: a cross tube havingend openings and an opening intermediate its ends; an integral tubeextending from said tube having access to said intermediate opening,said intermediate tube connected to said face mask; and a connector tubeswiveled on each end of said cross tube around said end openingsproviding the connections to said free ends of said flexible tubes ofsaid first and second conduit means.
 8. An anesthesia gas deliverysystem as defined in claim 7 wherein said filter means is connected tosaid flexible tube of said first conduit means to constitute its saidone end connection.
 9. An anesthesia gas delivery system as defined inclaim 7 wherein said filter means is provided on said coupler.
 10. Ananesthesia gas delivery system as defined in claim 7 wherein said filtermeans is connected to said flexible tube of said second conduit means.11. An anesthesia gas delivery circuit as defined in claim 1 whereinsaid breathing bag is readily detachable from association with saidfirst check valve means and is disposable.
 12. An anesthesia gasdelivery circuit as defined in claim 11 wherein said breathing bagcomprises a plurality of panels joined along their edges and made ofantistatic material and at least one panel including a conductiveportion.
 13. An anesthesia gas delivery circuit as defined in claim 11wherein said breathing bag comprises a plurality of panels joined alongtheir edges made of an antistatic material.
 14. An anesthesia gasdelivery circuit as defined in claim 11 wherein said breathing bagcomprising four panels joined along their edges.
 15. An anesthesia gasdelivery circuit as defined in claim 12 wherein said breathing bagincludes a neck and a bushing joined to said neck.
 16. In an anesthesiagas delivery system for providing an anesthetic gas to a patientincluding a gas communication means adapted to be placed in contact witha patient, connector means in gas flow relation to said communicationmeans and having a pair of connector elements, first and second conduitseach having one end in gas flow relation to a respective one of saidpair of connector elements, said first conduit receiving fluid exhaledfrom the patient, first check valve means connected to said firstconduit to prevent a reverse flow of exhaled fluid in said firstconduit, a breathing bag associated with said first check valve means,relief valve means in gas flow relation to said first check valve means,exhalation check valve means in gas flow relation to said relief valvemeans, absorber means in gas flow relation to said relief valve means,fluid inlet means for adding an additional fluid to the gas flow,anesthetic vaporizer means in gas flow relation to said absorber means,said anesthetic vaporizer being connected to said second conduit toprovide fluid for inhalation to the patient, and a filter means removingextraneous particles from the gas flow through the system, theimprovement wherein the gas communication means, connector means, firstand second conduits and the filter means are disposable and readilydetachable from said first check valve means and said anestheticvaporizer means.
 17. The system set forth in claim 16 wherein saidcommunication means is a face mask and said mask comprises a conductiveplastic face piece and a foam plastic cushion adapted to resilientlyconform to the facial contour of the patient and having a gas supplytube attachment means and wherein the cushion has a conductive coating.18. The system set forth in claim 16 wherein said connector means has aY configuration and comprises a hollow tee element having a leg and ahead with the leg of said tee element connecting to said communicationmeans, and said connector elements are rotatably fitted on opposite endsof the head and wherein said connector means is made of electricallyconductive plastic material.
 19. The system set forth in claim 16wherein said first and second conduits are corrugated tubes made ofelectrically conductive material.